Petrov types and special reference frames

摘要

The Petrov classification is studied with the language of spacetime splitting with respect to a generic timelike unit vector field. Canonical forms of the Weyl tensor for each Petrov type are introduced in terms of preferred reference frames. As an application, the canonical forms of the Bel-Robinson superenergy density and flux are constructed and applications to Bel's definition of gravitational radiation are considered. [References: 19]